Recently, there is provided a system according to which a control program of a programmable logic controller (PLC) is managed by a server and the control program managed by the server can be edited via a network.
A user inputs account information required for editing the control program to the server. If authentication succeeds, the control program can be downloaded, inspected, and edited. This eliminates the need to usually store the control program in a client terminal, thus making it possible to prevent leakage of the control program. However, this method cannot be used in an environment where a network cannot be used.
Patent Literature 1 discloses a method according to which a control program is made to operate only in a specific PLC.